From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754526AbdJIMq1 (ORCPT ); Mon, 9 Oct 2017 08:46:27 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42127 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754449AbdJIMpa (ORCPT ); Mon, 9 Oct 2017 08:45:30 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Nicholas Bellinger" , "Jiang Yi" Date: Mon, 09 Oct 2017 13:44:24 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 096/192] target: Fix COMPARE_AND_WRITE caw_sem leak during se_cmd quiesce In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jiang Yi commit 1d6ef276594a781686058802996e09c8550fd767 upstream. This patch addresses a COMPARE_AND_WRITE se_device->caw_sem leak, that would be triggered during normal se_cmd shutdown or abort via __transport_wait_for_tasks(). This would occur because target_complete_cmd() would catch this early and do complete_all(&cmd->t_transport_stop_comp), but since target_complete_ok_work() or target_complete_failure_work() are never called to invoke se_cmd->transport_complete_callback(), the COMPARE_AND_WRITE specific callbacks never release caw_sem. To address this special case, go ahead and release caw_sem directly from target_complete_cmd(). (Remove '&& success' from check, to release caw_sem regardless of scsi_status - nab) Signed-off-by: Jiang Yi Signed-off-by: Nicholas Bellinger Signed-off-by: Ben Hutchings --- drivers/target/target_core_transport.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -689,6 +689,15 @@ void target_complete_cmd(struct se_cmd * if (cmd->transport_state & CMD_T_ABORTED || cmd->transport_state & CMD_T_STOP) { spin_unlock_irqrestore(&cmd->t_state_lock, flags); + /* + * If COMPARE_AND_WRITE was stopped by __transport_wait_for_tasks(), + * release se_device->caw_sem obtained by sbc_compare_and_write() + * since target_complete_ok_work() or target_complete_failure_work() + * won't be called to invoke the normal CAW completion callbacks. + */ + if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) { + up(&dev->caw_sem); + } complete_all(&cmd->t_transport_stop_comp); return; } else if (!success) {